Crepe thread and fabric



Patented Jan. 3, 1939 UNITED STATES PATENT OFFICE A CREPE THREAD AND FABRIC Henry Dreyfus, London, England No Drawing. Application May 12, 1938, Serial No. 207,578. In 1934 Great Britain February 8,

14 Claims. (01. 117-2) This invention relates to.the manufacture of crepe threads of filaments of cellulose acetate or highly twisted threads of natural silk in the I gummed state, the crepe efiects appearing when the fabrics so formed are subjected to an aqueous scouring treatment. The fabrics obtained by this process are highly valued on account of their pleasing appearance and handle. The .produc- 15 tion of crepe fabrics in an analogous manner by the use of crepe threads of cellulose acetate has, however, been accompanied by difficulties. Generally the crepe efiect obtained by simply applying to cellulose acetate threads a twist of the order of that commonly employed in connection with natural silk, weaving the twisted threads into a fabric, and subjecting the fabric to a hot aqueous scouring treatment, is very unsubstantial and not comparable with that obtained with natural silk or with regenerated cellulose artificial silk. Moreover, the simple insertion of very high twists in cellulose ester yarns considerably reduces the tensile strength of such yarns and may even reduce the tensile strength so much as to render the products commercially useless.

It has now been discovered that crepe threads and fabrics of especially valuable properties may be obtained from cellulose ester materials by inserting a high twist in cellulose ester threads by a process in which during the insertion of at least the last part of the twist the threads are under the influence of steam or hot water, and

subjecting the cellulose ester threads to a process of partial saponificationbefore the threads are 40 woven and subjected to the usual hot scouring treatment. The saponification treatment may be applied to the threads before they are twisted or after they are twisted, the first of these methods being preferred. 'The saponification should be continuous along the length of the threads. 1

By means of this invention several very important advantages are secured. Thus, in the first place, a satisfactory crepe figure can be obtained by twisting to a much lower extent than is necessary if the saponification treatment is not applied, with the consequential advantage that the tensile strength of the threads is better preserved. In the second place, a bettercrepe a shrinkage in the hot scouring bath is obtained even though the crepe threads may be twisted to a degree less than is necessary if the saponification treatment is not applied, and, in the third place, satisfactory crepe effects can be obtained with a much shorter period of treatment in the scouring bath than has hitherto been considered necessary. Thus, whereas, for example, a crepe fabric containing cellulose acetate yarns of 170 denier which have been twisted to 70 turns per inch (by a process in which the yarns are under 10 the influence of steam during the insertion of the last part of the twist) shrinks by about 20% of its width on scouring for two hours in a boiling soap bath, a similar fabric containing cellulose acetate yarns of 170 denier which have been surl5 face 'saponified so that they suffer a loss in weight of about 5% and have then been twisted to only turns per inch by a similar steamtwisting process, shrinks by about of its width on scouring for only fifteen minutes at C. in a 20 similar soap bath. The final shrunk width obtained may, of course, be controlled, e. g. by an adjustment of the twist inserted in the yarn or by a control of the tension operating upon the fabric particularly during the drying and finish- 25- ing stages.

' The process may be applied to yarns of any cellulose ester but is of especial importance in connection with yarns of. cellulose acetate. As examples of other cellulose esters theremay be 30 mentioned cellulose formate, propionate and butyrate and oxyethyl cellulose acetate. Very valuable results may be obtained by employing yarns of cellulose esters of high viscosity characteristics, for example cellulose acetate or other 35 cellulose esters as described in U. S. Patent No. 1,708,787. Thus, cellulose acetate may have a viscosity of 30 or'more, and preferably 50 to or 200 or more as measured by comparing the viscosity of a 6% solution of the cellulose acetate 40 in acetone with that of glycerine taken as a standard of 100.

The saponification may be such as to reduce the acidyl content of the cellulose ester substantially throughout the cellulose ester thread, 45

other alkali salts of weak inorganic ororganic acids, ammonia and organic bases, e. g. methylamine, ethylamine and ethylene diamine.

The degree or saponiflcation effected may be considerable, e. g-. such as to cause a loss of 10 to 30% or more of the weight or the material treated, but preferably a surface saponiflcation such asto cause-a loss of only 3to 5% up to in the weight of the material is efiected. A suitable method oi! efiecting surface saponiflcation mounting to a loss in weight of 3 to 5% is to treat the cellulose ester yarns with the theoretical amount of caustic soda or equivalent agent required to eflect such saponiflcation, the caustic soda or other agent being employed in aqueous solution in an amount of liquid equal to about 10 times the weight of the cellulose ester yarns treated and applied for about one hour at 80 C.

To eflect greater degrees of saponiflcation cordrums, as described in U. S. Patents Nos. 1,884,622

and 1,884,623. Another valuable method is to effect the saponiflcation under conditions in which it takes place only very slowly. Thus, the conditions of concentration of the saponifyin agent and temperature may be adjusted to result in only a 3-5% loss in weight at the end of 8 hours treatment. As an example of such a slow saponiflcation, there may be mentioned treatment with a 0.1 to 0.6% solution of ammonia at 28 C. for 8 hours.

As indicated above, the saponiflcation treatment is preferably applied to the yarns prior to the twisting of the yarns. However, it may also be applied to the yarns after the twisting operation. The treatment may be efiected by immersing hanks of yarn in the saponifying solution or by passing a solution of a saponifying agent backwards and forwards through the windings of bobbins of the yarn, or, where a fairly rapid saponiflcation is eifected, the yarn may be treated while it is travelling from one point to another, e. g. in a bobbin to bobbin winding operation, by contacting the yarn during its travel ,with a wick, roller or other device supplied with the saponifyin a ent.

The twisting of the yarns, as stated above, is effected by a process in which at least the last part of the twist is inserted while the thread is under the influence of steam or hot water. It is fundamental according to the process of this invention that the steam or hot water should be applied to the threads while the twist is actually being inserted, i. e. that the steam or hot water is applied to the travelling thread over at least a portion of that part of its track in which twisting is actually taking place. .When using steam it is of great advantage to have moisture present. Thus,'the thread may be passed through a substantially closed chamber maintained full of steam under such conditions that moisture is present, so that at least a portion of that part of the track-of the running thread in which twisting actually takes place is within the steam chamber. Twist is thus insertedwhile the thread is under the influence of a hot medium which is substantially entirely aqueous.

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stantially in line with the axis of rotation of the package and is thereafter wound on a-bobbin or the like, the thread being passed through the steam chamber or the hot water on its way from the guide to the bobbin. In this way the thread is subjected to the action of steam or hot water during the actual insertion of twist.

On the other hand, any other suitable crepe twisting device may be employed. For example a ringe twister may be used for the crepe twisting of thread consisting of discontinuous filaments.

The twisting spindle,-the guide fixed in line with the axis of the spindle, and the steaming device or'the hot water treatment device, should be so arranged that the twist resulting from the rotation of the package is at least partly inserted while the thread is under the influence of the steam or hot water. For example, when twisting the thread by the rotation of a package from which the thread is being drawn oil, if the freedom of the thread to rotate within the balloon guide or other guide preceding or forming part of the treatment device is unduly restricted, e. g. by causing the thread to change direction materially at the guides, the insertion of twist while the thread is under the influence of the steam or hot water may be restricted to an undesirable extent or substantially prevented and the resulting crepe threads may not have the valuable properties which may otherwise be secured. Thus, when using a twisting device of the kind in which thread is drawn 03 over the endof a rotating package, it is advantageous to arrange that the path of the thread after leaving the balloon guide and through the treatment device, is substantially in line with the axis of the spindle.

In the case of a ring twister where twisting is effected by the rotation of a package onto which the thread is being wound, the thread passing through the steam chamber or the hot water on itsway from the let-oil? device to the twisting spindle, a change of direction at the point at which the thread leaves the steam chamber or the hot water is of less .importance as the thread 'remains under the influence of the steam or hot' water for a short time after leaving the-"steam chamber'or hot water as the case may be. If desired, the above-mentioned twisting devices, in which the thread is drawn 011 over the end of a rotating package, may be provided with a device which restricts the ballooning oi the .thread or the tendency oi. twistto run back to the package. As examples of such devices may be mentioned iiyers and the floating ring device described in U. S. Patent No. 1,784,581. The latterdevice is of particular value when the thread to be twisted is of very low twist, for example less than about 1 turn per inch.

when employing steam the new process may be carried out-using a vertical twisting spindle of the type in which thread is drawn oflupwardly over the end of a rotating package through a guide substantially in line withthe axis of the spindle, provided with a small chamber situated vertically above the spindle. The chamber is provided with small holes, top and bottom, to permit passage of the thread, and

also with a steam inlet. If desired, a single steam chamber may be arranged to serve a number of spindles, being provided with inlet and outlet holes for the thread of each spindle. Such an apparatus may conveniently consist of a horizontal pipe mounted over a row of spindles and provided with eyes of porcelain, stainless steel, or other suitable material atappropriate points on top and bottom for the entrance and exit of the threads. The diameter of the pipe is sufficient to afford the thread the requisite length of travel in the steam. Steam may be admitted to the pipe at one point or at more than one point as may be necessary according to the length of the pipe, to secure sufiiciently uniform conditions of steaming as between the threads from the difierent spindles.

If desired the pipe may be of less diameter than affords the thread the requisite length of travel and be fitted with upwardly projecting vertical tubes communicating with the inside of the pipe at their lower ends, closed at their upper ends except for eyes for the passage of the thread,

and of such length as to aiTord, together with the diameter of the pipe, the required length of path in the steam for the thread. The threads enter by eyes in the lower side of the horizontal pipe and leave by the eyes in the upper ends of the vertical tubes.

At the point at which the thread from the twisting spindle enters thesteam chamber, it is advantageous to arrange a free escape of steam on to the thread as it is drawn oil from the spindle. A shield, for example in the form of a funnel, may, if desired, be fitted around the thread approaching the steam chamber in order to maintain an atmosphere of steam around the thread.

The presence of the desired moisture may be assured by arranging for the condensation of steam. Dry steam may be passed through water so as to saturate the steam and the requisite moisture produced by cooling in the steam chamber. The above mentioned form of steam chamber comprising a horizontal pipe with upwardly projecting tubes to aiTord the requisite length of path in the steam for the threads is advantageous when condensation of steam is desired. Another method of ensuring the presence of mo sture is to Wet the thread with water; for example the bobbins of thread may be'wetted before the twisting operation or better, water may be applied to the thread, by means of a wick or other device, after the thread leaves the spindle and prior to its entering the steaming device. The water may contain a substance which facilitates wetting of the thread by water.

Good results may be obtained by using steam at above C. Steam temperatures in the neighbourhood of 100 0., for example to or 98 to 100 C. are advantageous. Steam at about atmospheric pressure, e. 'g. slightly above atmospheric pressure, is conveniently employed; However, if desired steaming may be effected with steam at any desired superatmospheric pressure, e. g. steam at 10 to 25 lbs. per square inch.

The path of the thread through the steam chamber may be comparatively short, for example 1 to 3 inches, though longer paths may be employed if desired, for example3 to 6 inches.

Treatment of the thread with hot water during twisting may be effected by drawing the thread .oif from a twisting spindle and passing it upwardly through a suitable receptacle containing hot water and having a small hole below the water level for the passage of the thread, the thread then passing to a winding device. The hole may be, for example, about 3 2 of an inch in d ameter and may be provided with means adapted to lead away and prevent from reaching the twisting spindle, any water issuing from the hole. Ii desired, the hole may take the form of a short tube of fine bore, fixed in the receptacle, whereby the flow of water from the receptacle at the to the twisting spindle.

point of entrance of the thread may be reduced. A similar arrangement may be used when crepe twisting is effected as the thread is wound on to a rotating package. In this case the thread may conveniently pass downwards through the "water Another method is to supply hot water to the thread. For example, the thread may be caused to pass in contact with a horizontally disposed roller, preferably circumferentially grooved, arranged to rotate in a bath of hot water and so to carry water to the thread.

The duration of the treatment with hot water may be relatively short, such as may be secured when the thread is travelling at a speed of 2-10 metres per minute and is in contact with hot water for l-3 inches of its travel. Lengthier treatments may, however, be employed.

The temperature of the water may be 80-l00 C., for instance 90-100 C. If desired, the hot water may be employed under pressure, for example 2-10 or 15 pounds or more per square inch. The use of pressure enables the water to be employed athigher temperatures than is possible under atmospheric pressure. By using pressure, therefore, the temperature of the water may be above 100 C. and up to the boiling point of .water at the pressure employed. Water may be employed under pressure, however, wl1en the temperature is below 100 C. The hot water may contain agents which facilitate the wetting of the threads.

The initial thread may already be twisted to a small degree. for example up to 10 turns per inch, e: g. to 2-5 turns per inch or to such small degree as is commonly applied to artificial silk continuously with the spinning thereof.

'In carrying out the new process the crepe twist may be appl ed in a single stage. If desired, however, the crepe twist may be applied in two or more stages, the final stage of twisting being effected whilst steaming the thread in a substantially closed chamber or whilst treating the thread with hot water.

When the crepe twist is applied in two or more stages the advantages of the process may be obtained when not only the final stage of the crepe twisting but an earlier stage or stages of twisting are also effected while steaming the thread or treating it with hot water. In fact itis of great advantage to effect, while steaming the thread or treating it with hot water. any ap lication of twist beyond the point at which twist ng would result in weakening of the thread if the said twisting were effected without-the steaming or hot water treatment.

The precise degree of twist beyond which it is advantageous to steam or treat with hot water during tw sting depends upon th'etotal'denier of the thread and the number of its constituent filaments. Generally at least the last half or two thirds of the total crepe twist should be applied whilst steaming the thread or treat ng it with hot water. I

If the crepe twist is applied in two or more stages the twist may be divided between the twisting stages in various proportions. Twist applied in the absence of the steam or hot water treatment should not be of such degree as to damage the thread. To this end, as indicated previously, twisting without the steam or hot water treatment should not be effected where the twist applied is sufiicient to result in substantial weakening of the thread.

A particularly convenient method of working half of the total crepe twist without the steam or hot water treatment, say up to 10 or 15-25 or even in some cases up to 30 turns per inch, and

then to complete the crepe twist while steaming the thread or treating it with hot water.

The degree of twist which, in accordance with the present invention is necessary to impart creping power is, as stated above, lower than the twist necessary to impart crepi power if the saponification treatment characteristic of this invention is not applied. Thus, it has been found that excellent crepe effects may be obtained by the use of crepe threads produced in accordance with this invention which have been twisted to 40-50 or 60 turns per inch as compared with the -80 turns per inch necessary if the saponiflcation treatment is not applied.

The highly twisted crepe threads may be incorporated in the fabrics in various ways, for example the weft alone may be wholly or partially composed of such threads or the warp may also contain them. Valuable fabrics may be produced by employing warp threads of relatively low twist and in the weft both crepe threads having a lefthand twist and crepe threads having a right-hand twist, pairs of threads of left-hand twist alternating with pairs of threads of right-hand twist.

As usual in the production of crepe fabrics, the highly twisted crepe threads are woven into fabric form and the fabric so' obtained is subjected to a hot aqueous scouring treatment. As indicated above, it is not necessary in accordance with this invention that this scouring treatment should be so drastic as is necessary to produce satisfactory results in the absence of the saponifying treatment characteristic of the invention.

Having described my invention, what I desire to secure by Letters Patent is:

1. In the production of cre'pe threads having a .basis of organic esters of cellulose and of fabrics containing such threads, the steps of forming crepe threads by inserting a-high degree of twist in threads of organic esters of cellulose by a process in which at least the last part of the twist is inserted while the threads are under the influence of a hot aqueous medium, and subjecting the threads of organic esters of cellulose, in unwoven form, to partial saponiflcation.

- 2. In the production of crepe threads having a basis of organic esters of cellulose and of fabrics containing such threads, the steps of subjecting threads of organic esters of cellulose to partial saponiflcation and inserting a high degree of twist in such partially saponifled threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of a hot aqueous medium.

3. In the production of crepe threads having a basis of organic esters of cellulose and of fabrics containing such threads, the steps of subjecting threads of organic esters of cellulose to partial saponification and inserting a high degree of twist in such partially saponifled threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of steam.

4. In the production of crepe threads having a basis of organic esters of cellulose and of fabrics containing such threads, the steps of subjecting threads of organic esters of cellulose to surface saponification and inserting a high degree of twist in such surface-saponifled threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of steam.

5. In the production of crepe threads having a basis of cellulose acetate and. of fabrics containing such threads, the steps of subjecting threads of cellulose acetate to surface saponification and inserting a high degree of twist in such surfacesaponified threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of steam.

6. In the production of crepe threads having a basis of cellulose acetate and of fabrics containing such threads, the steps of subjecting threads of cellulose acetate to surface saponification to effect a loss of 3-5% in their weight and inserting a high degree of twist in such surface-saponifled threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of steam.

7. In the production of crepe threads having a basis of cellulose acetate and of fabrics containing such threads, the steps of subjecting cellulose acetate threads to treatment with caustic soda solution to efiect a loss of v3--5% in their weight, and inserting a high degree of twist in the treated threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of steam.

8. In the production of crepe threads having a basis of organic esters of cellulose and of fabrics containing such threads, the steps of subjecting threads of organic esters of cellulose to partial saponification and inserting in such threads a degree of twist lower than that necessary to impart creping power to similar threads which have not been saponifled, at least the last part of the twist being inserted while the threads are under the influence of ahot aqueous medium.

9. Process for the production of fabrics exhibiting crepe effects, which comprises'subjecting threads of organic esters of cellulose to partial saponiflcation, inserting a high degree of twist in such partially saponifled threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of a hot aqueousmedium, weaving such threads into fabric form and subjecting the fabric to treatment in a hot aqueous scouring bath.

10. Process for the production of fabrics exhibiting crepe effects, which comprises subjecting threads of cellulose acetate to partial saponification, inserting a high degree of twist in such partially saponifled threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of steam, weaving such threads into fabric form and subjecting the fabric to treatment in a hot aqueous scouring bath.

11. Process for the production of fabrics exhibiting crepev effects, which comprises subjecting threads of cellulose acetate to surface saponiflcation to effect a loss of 3-5% in their weight, inserting a high degree of twist in such saponifled threads by a process in which at least the last part of the twist is inserted while the threads are under the influence of steam, weaving such threads into fabric form and subjecting the fabric to treatment in a hot aqueous scouring bath.

12. Process for the productionof fabrics exhibiting crepe effects, which comprises subjecting threads of cellulose acetate to treatment with caustic soda to eflect a loss of 3-5% in their weight, inserting a high degree of twist in such treated threads by a process in which at least the are under the influence of steam, weaving such threads into fabric form and subjecting the fabric to treatment in a hot aqueous scouring bath. 13. Process for the production of iabrics exhibiting crepe eflects, which comprises inserting hibiting crepe effects, which comprises subjecting threads of an organic ester of cellulose to partial saponiflcation, inserting in such partially saponified threads a degree of twist less than that necessary to impart creping power to similar threads which have not been saponifled, at least the last part of the twist being inserted while the threads are under the influence of steam, weaving such threads into fabric form and subjecting the fabric to treatment in a hot aqueous m scouring bath.

HENRY DREYFUVS. 

